Malte about some of his work at Oracle

The Sun ODF Plugin for Microsoft Office and the Excel issue after uninstalling or upgrading the Plugin

Many people complain about an issue they have with Excel after uninstalling or upgrading the Sun ODF Plugin for Microsoft Office: When starting Excel, Excel complains that the Add-In odfaddin.xla can't be found: 'C:\\Program Files\\Sun\\Sun ODF Plugin for Microsoft Office <old version>\\converter\\odfaddin.xla' could not be found. (...)

I would like to point out that this is not an issue from the ODF Plugin installer, but in Excel itself:

The ODF Plugin installer writes some HKEY_LOCAL_MACHINE entries into the registry to activate the Plugin, and these entries are removed when uninstalling the Plugin, or point to the correct version when doing an upgrade installation. But for some reason, Excel will put a reference to the Add-In file odfaddin.xla into the user's configuration (HKEY_CURRENT_USER) when starting Excel after the ODF Plugin installation. This entry - of course - won't be removed from the installer when uninstalling the ODF Plugin.

So to get rid of the annoying error message, you need to remove that reference yourself:

If it doesn't work (which seems to happen at least in Office 2007 after upgrading the ODF Plugin), remove the reference to the old Add-In in the registry directly: HKEY_CURRENT_USER\\Microsoft\\Office\\<version>\\Excel\\Options => "OPEN"="\\"C:\\\\Program Files\\\\Sun\\\\Sun ODF Plugin for Microsoft Office <old version>\\\\converter\\\\odfaddin.xla\\""

In more detail - this happens in the different phases when installing the ODF Plugin, running Excel and then uninstalling or upgrading the ODF Plugin:

So if Excel has a reference to the Add-In, Excel should probably simply disable the Add-In when it doesn't exist anymore, instead of complaining over and over again. Or at least ask the user whether or not to keep the entry...